Improvement in screw-drivers



l. H. DAVIS.

Screw-Drivers.

NOQl @1,857, I Patented AugustlQ, 1873.

NTTED STATEs PATENT OFFICE;

v' JOSEPH VH. DAVIS, OF LIVINGSTON COUNTY, MISSOURI.

IMPROVEMENT IN SCREW-DRIVERS.l

Specification forming part of Letters Patent No. 141,857, dated August 19, 1873; application filed July B, 1873.

To all whom 'it may concern: 1

Beit known that I, J osEPH H. DAVIs, of Livingston county, Missouri, have invented certain new and useful Improvements in Screw- Drivers, of which the following is a speciiication, reference being had to the accompanying drawings.

The invention relates to providing a screwdriver with a pair of clamps, supplied at their l'ower ends withfhooks properly arched to receive the head of the screw, and pivoted at about their center to a stand, movable upon the blade of a screw-driver, their upper ends being connected and directed by a guide or collar xed upon the blade of the screwdriver, upon which are provided springs to eX- pand the upper and so contract the lower ends of the clamps about the point of the blade. The clamps are thus movable upon the blade, and can be operated to grasp the head of a screw for either the purpose of assisting in inserting or withdrawing it.

Figure l is a side view of a device embodying the elements of the invention. Fig. 2 is a sectional view of same through the line w x.

A in the accompanying drawings is the blade of a screw-driver, which tapers slightly for a certain distance below the handle B, near which and upon the tapered portion is lirmly, but not tlxedly, secured the collar or guide D, having the rectangular aperture a, in the center of which is cut the recess b, into which the blade A fits snugly, while the remainder of the aperture corresponds in width to the clamps E, the upper parts of which move in and are directed by the guide D. The clamps E consist of bars of metal, in outline conforming generally to the blade A. Their upper ends are provided with the flan ges el to facilitate the expansion of the clamps, which pass through the guide/7d on either side thereof, and adjacent to this point are provided with the guide-slot f, to allow the clamps to be moved a proper distance, up or down. At a suitable distance below the guide D the clamps are pivoted in the ears h of the pivotstand F, through the center of which the blade A passes, and which is movable, up or down, thereon. The lower ends of the clamps are each provided with an arch or hook, i, the section of the opening or interior of which corresponds to the section of the head of a screw ot' ordinary form, the edges of these hooks being provided with a recess, l, opposite eachother, and of proper dimensions. The position of the hooks i is such that, when the clamps E are being forced downward as far as possible and the point or edge of the driver inserted in the creasel of the screw to be operated upon, the upper horizontal surface of the hooks shall be in contact with the corresponding surface of the head of the screw. To the inner surfaces of the clamps, adjacent to the lian ges d, are firmly attached the upper ends of the bow-springs m, the arches of which impinge upon the opposite sides of theblade A, acting outwardly from the blade, and forcing the upper ends of the clamps E apart until they come in contact with the sides of the aperture a in the guide D, which serves to restrain the upper ends of the clamps E in such position that they may readily be operated by the hand grasping the handle B.

When it is desired to remove a screw, draw up the clamps until the edge of the blade A is fully exposed, and insert in the crease in the head of the screw; draw the screw in the vusual manner until the head is raised; then expand the hooks t by compressing the lian ges ol; force the clamps E down and allow them to close upon the screw, which holds the screw steadily in position and permits it to be readily withdrawn.

When it is desired to insert a screw, force the clamps E to their lowest position, expand the hooks i, place the point of the blade A in the crease of the screw, allow the clamps to close, whereby the screw is vheld in position and may be easily operated, the hooks t' slipping over the head of the screw as it enters the material.

To remove the clamps E and their immediate appurtenances, force the guide D down the tapered part of the blade A until it is loosened, when the blade can be withdrawn.

I am aware that screw-drivers have been made with spring-j aws compressible about the head of a screw by means of a sliding clamp,

and also that screw-drivers have been made with jaws operated by springs for a similar purpose; but these devices require two hands in their operation, and I do not therefore claim such; but

What I do claim as my invention, and dcsire to secure by Letters Patent, is-

The clamps E, provided with the hooks i, and so contracted by the guide D as to be operable by the hand grasping the handle B,

` in combination with the pivot-stand F and springs m, when arranged upon the blade A, substantially as shown and described.

In testimony that I claim the foregoing improvement in screwdrivers, as above described, I have hereunto set my hand and seal this 30th day of June, 1873.

JOSEPH H. DAVIS. [L s] Witnesses J. G. FOSTER, JOSEPH W. MILLER. 

